The watercress season is upon us, so make the most of it. Not only is it a home-grown product with, so we are told, medicinal properties, it also has a deep, intense flavour rarely found in vegetables. This is a superb warm starter, but works equally well as a cold salad - just adjust the seasoning after it cools.

Wash the lentils in cold water, then put them in a saucepan and cover with plenty of fresh water. Bring up to a boil, then turn down the heat and simmer for 15 minutes, or until just cooked.

While the lentils are cooking, put 40g of the watercress, the parsley, oil, garlic, salt and pepper in a food processor, and blitz. Cook the asparagus for two minutes in simmering, salted water and drain. Keep warm.

Once the lentils are cooked, drain and stir into the watercress 'pesto'. Check the seasoning - you'll probably need more salt. To serve warm, toss together the lentils, asparagus and remaining watercress. The cheese slices should be integrated carefully while you're plating up, so that they don't break up. Finally, drizzle over a little oil and serve with a lemon wedge.